1. Field of the Invention
This invention relates generally to a light emitting diode, and is directed more particularly to a green light emitting diode of a high light emitting efficiency.
2. Description of the Prior Art
Light emitting diodes are known which use gallium phosphide (GaP), and which will emit red, yellow or green light.
In general, when a green light emitting diode is employed for displaying, the green light can be easily noticed as compared with the other color lights, and a viewer's eyes are not fatigued as much with the green light. In practice, however, the green light emitting diode have not been so used as much as a red light emitting diode.
It is well known that it is required, in order to enhance the light emitting efficiency of a green light emitting diode, that nitrogen N, which may become the light emitting center, exist near or adjacent the PN junction. However, even if nitrogen N is sufficiently diffused over the epitaxial layer having the PN junction according to the method disclosed in the U.S. Pat. No. 3,893,875 which issued on July 8, 1975, and whose assignee is the same as that of the present application, this is not sufficient to provide a green light emitting diode having high light emitting efficiency which can be manufactured with high reproducibility and yield.